In order to prevent undesired removal of a connector fitted with a mating connector, a connector normally has engagement portions which engage with other engagement portions of the mating connector after the connector is fitted with the mating connector. Typical engagement portions are locking structures such as locking hooks, while ones of a mating connector are slits or grooves with which the locking hooks can engage. Conventionally, a connector with locking structures comprises a control mechanism for controlling the above-mentioned engagement, especially, the positions of the locking structures. The conventional control mechanism includes two buttons provided on opposite sides of the connector in a lateral direction. When the buttons are pinched and are pushed inwardly by two fingers of a user, the locking structures do not work for a mating connector so that the engagement is released if it is established before or that the connector can be easily fitted with the mating connector when being connected to the mating connector.
However, in some situations insufficient space is available to provide buttons on opposite sides of the connector and/or access space to operate these buttons is limited. In such a situation, it is preferred to have a connector that can engage the connector with or to release the connector from a mating connector or other counterpart by operating only a single button.
On the other hand, multiple locking structures may be desired to establish optimal engagement between the connector and the mating connector or other counterpart.